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ABSTRACT: Lurgi coal gasification wastewater (LCGW) is a refractory wastewater, whose anaerobic treatment has been a severe problem due to its toxicity and poor biodegradability. Using a mesophilic (35±2°C) reactor as a control, thermophilic anaerobic digestion (55±2°C) of LCGW was investigated in a UASB reactor. After 120 days of operation, the removal of COD and total phenols by the thermophilic reactor could reach 50-55% and 50-60% respectively, at an organic loading rate of 2.5 kg COD/(m(3) d) and HRT of 24 h; the corresponding efficiencies were both only 20-30% in the mesophilic reactor. After thermophilic digestion, the wastewater concentrations of the aerobic effluent COD could reach below 200 mg/L compared with around 294 mg/L if mesophilic digestion was done and around 375 mg/L if sole aerobic pretreatment was done. The results suggested that thermophilic anaerobic digestion improved significantly both anaerobic and aerobic biodegradation of LCGW.
Bioresource technology 02/2011; 102(3):2441-7. · 4.25 Impact Factor
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ABSTRACT: Moving bed biofilm reactor (MBBR) was used to treat real coal gasification wastewater. Nitrification of the MBBR was inhibited almost completely during start-up period. Sudden increase of influent total NH3 concentration was the main factor inducing nitrification inhibition. Increasing DO concentration in the bulk liquid (from 2 to 3 mg/L) had little effect on nitrification recovery. Nitrification of the MBBR recovered partially by the addition of nitrifying sludge into the reactor and almost ceased within 5 days. Nitrification ratio of the MBBR achieved 65% within 12 days by increasing dilute ratio of the influent wastewater with tap water. The ratio of nitrification decreased to 25% when influent COD concentration increased from 650 to 1000 mg/L after nitrification recovery and recovered 70% for another 4 days.
Journal of Environmental Sciences 01/2011; 23(4):568-74. · 1.66 Impact Factor
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ABSTRACT: A two-continuous mesophilic (37 ± 2°C) UASB system with step-feed was investigated as an attractive optimization strategy for enhancing COD and total phenols removal of the system and improving aerobic biodegradability of real coal gasification wastewater. Through the step-feed period, the maximum removal efficiencies of COD and total phenols reached 55-60% and 58-63% respectively in the system, at an influent flow distribution ratio of 0.2 and influent COD concentration of 2500 mg/L; the corresponding efficiencies were at low levels of 45-50% and 43-50% respectively at total HRT of 48 h during the single-feed period. The maximum specific methanogenic activity and substrate utilization rate were 592 ± 16 mg COD-CH(4)/(g VSS d) and 89 ± 12 mg phenol/(g VSS d) during the step-feed operation. After the anaerobic digestion with step-feed, the aerobic effluent COD concentration decreased from 270 ± 9 to 215 ± 10 mg/L. The results suggested that step-feed enhanced the degradation of refractory organics in the second reactor.
Bioresource technology 10/2010; 102(9):5454-60. · 4.25 Impact Factor
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ABSTRACT: Coal gasification effluent is a typical refractory industrial wastewater with a very poor anaerobic biodegradability due to its toxicity. Methanol was introduced to improve anaerobic biodegradability of real coal gasification wastewater, and the effect of methanol addition on the performance was investigated in a mesophilic upflow anaerobic sludge bed reactor with a hydraulic retention time of 24 hr. Experimental results indicated that anaerobic treatment of coal gasification wastewater was feasible with the addition of methanol. The corresponding maximum COD and phenol removal rates were 71% and 75%, respectively, with methanol concentration of 500 mg COD/L for a total organic loading rate of 3.5 kg COD/(m3 x day) and a phenol loading rate of 0.6 kg/(m3 x day). The phenol removal rate was not improved with a higher methanol concentration of 1000 mg COD/L. Substrate utilization rate (SUR) tests indicated that the SURs of phenol were 106, 132, and 83 mg phenol/(g VSS x day) at methanol concentrations of 250, 500, and 1000 mg COD/L, respectively, and only 45 mg phenol/(g VSS x day) in the control reactor. The presence of methanol could reduce the toxicity of coal gasification wastewater and increase the biodegradation of phenolic compounds.
Journal of Environmental Sciences 01/2010; 22(12):1868-74. · 1.66 Impact Factor
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ABSTRACT: Molecular chaperones and cochaperones are known to participate in nuclear receptor-mediated gene expression in addition to providing the appropriate conformation for hormone binding. It has been reported that Bag-1M (Bcl-2 associated athanogene 1M) downregulates the transactivation function of the glucocorticoid receptor (GR). Here, we demonstrate that Bag-1M downregulates the glucocorticoid function via binding to distinct amino acid sequences in the hinge region of the GR. In cells expressing the human metallothionein IIa gene, overexpression of Bag-1M resulted in an in vivo dissociation of the DNA-receptor complex and a decrease in glucocorticoid-mediated transcription, indicating that this cochaperone acts as a negative regulator of GR action. In Bag-1M-expressing cells, this cochaperone is recruited with the GR to genomic hormone response element following glucocorticoid treatment. In line with this, small interfering RNA knockdown of the cellular level of Bag-1M enhanced DNA binding by the GR, resulting in a robust increase in transcriptional activity. These findings identify a regulatory mechanism, downstream of hormone binding, used by Bag-1M for attenuating GR action in response to its changing cellular levels.
Journal of Molecular Biology 10/2008; 384(1):22-30. · 4.00 Impact Factor
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ABSTRACT: This study aimed to investigate the inhibitory effect of tyroservaltide (YSV) on the human hepatocarcinoma BEL-7402 transplanted into nude mice and to explore its possible anti-tumor mechanism. Nude mice bearing xenografts of the human BEL-7402 hepatoma were given daily i.p. injections of YSV or saline (as a control) after the tumor were transplanted. Calculating tumor volume and measuring tumor weight determined the extent of inhibition of xenografts. The ultrastructure of tumor cells was observed by electron microscopy. Proliferating cell nuclear antigen (PCNA) expression in tissues of the YSV-treated group was observed by immunohistochemistry. Apoptosis of tumor tissue cells was assayed by the terminal transferase uridyl nick end labeling (TUNEL) method. At doses of 80 microg/kg/d and 160 microg/kg/d, YSV could significantly inhibit growth of tumors transplanted into nude mice, with inhibition rates of 60% and 64%, respectively, compared with that of the controls (P < 0.05). Moreover, YSV changed the ultrastructure of tumor cells, resulting in necrosis and apoptosis of the tumor cells. Compared with the saline group, the expression of PCNA in tumor tissue decreased and the count of apoptotic cell increased. Therefore, YSV can significantly inhibit the growth of human hepatocarcinoma BEL-7402 in nude mice, decrease the expression of PCNA in tumor tissue, and induce tumor cell apoptosis.
Cancer biology & therapy 09/2005; 4(9):993-7. · 2.64 Impact Factor
